1. Field of the Invention
The present invention relates to a stretch fabric composed of a Raschel warp knit fabric, particularly to a stretch fabric suitably used as a medical material for covering or bandaging a curved or irregularly-shaped object or a portion of a human body, or as a reinforcement for a molded object having a curved or irregular surface, and to the use thereof.
2. Description of the Related Art
It has been well-known to use a glass fiber cloth as a fiber reinforcement for a molded plastic figure such as orthopedic cast. When orthopedic cast is manufactured, a warp knit fabric substrate of glass fiber yarns in which inlaid yarns are inlaid into a ground fabric structure of a chain stitch or others by using a warp knitting machine with a plurality of guide bars such as a Raschel warp knitting machine is often used as a casting tape. Generally, a mold for orthopedic surgery plastic cast is a human body having irregular and curved surfaces, and it has been also known that a stretchable knit fabric is used in the preparation of the orthopedic cast for imparting the irregular or curved surfaces with a elastically recovering properties as seen in a casting tape or a substrate for orthopedic cast (see Japanese Unexamined Patent Publication No. 62-82957; U.S. counterpart, U.S. Pat. Nos. 4,683,877, 4,893,617, 5,042,464). As disclosed in Japanese Unexamined Patent Publication No. 62-87162 (U.S. counterpart, U.S. Pat. No. 4,667,661), the casting tape for the orthopedic surgery is used while being coated with a water-curable non-adhesive resin composed of a resin such as polyurethane and containing wetting agent.
When the orthopedic cast is prepared it has been known to use a casting tape of a stretchable Raschel warp knit fabric incorporating elastomeric fibers or crimpt yarns of synthetic fibers such as polyester fibers, into the knit structure to be fit to the irregular surface of the affected part such as bone fracture, dislocation, distortion or others (see, for example, Japanese Unexamined Patent Publication No. 63-11165 (U.S. counterpart; U.S. Pat. No. 4,668,563) and Japanese Unexamined Patent Publication No. 2-71746 (U.S. counterpart; U.S. Pat. No. 4,984,566). The fiber reinforcement stretch fabric substrate such as the stretchable casting tape formed of stretchable fiber material, however, is expensive in material cost as well as problematic in functions as described below.
The fabric is liable to bind tight the affected part to interrupt the blood circulation while the resin impregnating the fabric when the orthopedic cast is manufactured is curing, since a large stretch-back property of the elastomeric polyurethane fiber is applied to the stretch fabric substrate containing the same, and also there are problems in the moldability or handling of the gypsum in that the polyurethane elastomeric fiber may become brittle due to the reaction with the resinous component or the gypsum may be difficult to be cut after being cured. On the other hand, also in a Raschel warp knit fabric substrate in which the textured yarns of synthetic fiber are used, there is a problem in that a casting tape having a favorable stiffness required for the moldability and fiber-reinforcement function of the gypsum is difficult to obtain.
The knitting of a warp knit fabric by using a Raschel warp knitting machine with a fall-plate has been known as a method for providing a tuck pattern of thick yarns to a warp knit fabric and a method for knitting a fabric in which wales of chain stitches of tuck warp are coupled to each other so that part of the ground fabric structure is allocated to the tuck warp (See “Warp Knitting Technology”, pages 325 to 332, by D. F. Paling; FTI: Columbine Press, 1970). The known method in which the fall-plate is adopted has been used for knitting a Raschel knit fabric having a pattern of loops caused by the fall-plate.
In the drawings, G represents a guide bar; F a front guide bar lapping movement; B a back guide bar lapping movement; 1 a tuck warp; 2 a warp for a ground stitch (a chain stitch); 3, 3a, 3b, 3c, 3d and 3′ a tuck loop; 20 a double-sided knit fabric; 21 and 22 a ground fabric of the double-sided knit fabric, respectively; 100 a device for measuring an elongation; 101 a test piece; 102 a machine base table; 104 an upper clamp; 105 an aluminum pipe; 106 a ruler; 107 a weight; and A-A′ a sectional line.